Air quality integrated modelling in Turin urban area

According to EU Directive 96/62/CE, Piedmont Region set up a project to perform air quality assessment by means of an integrated modelling system. To verify the system reliability, simulations of two air pollution episodes have been programmed. Results obtained from the simulation of a winter peak episode are presented here. The model domain covers an area of 80x80km^2 centred on the city of Turin and the simulation period lasts four days (28th-31st January 2000). SPRAY Lagrangian particle model, coupled with the MINERVE diagnostic wind field code, has been used to reconstruct the episode, taking into account CO and NO"x. Computed ground level concentrations have been compared with measured values at different sites (urban, sub-urban and remote). The analysis of results reveals that the system capability in reproducing concentrations behavior is higher in ''urban background'' or suburban stations, and lower in sites heavily affected by nearby traffic; this is attributed to spatial resolution effects, local traffic emissions modulation and urban boundary layer modelling. These aspects are discussed, highlighting possible improvements.